The structure disclosed in Japanese Unexamined Patent Publication No. 2002-259054 is known as that of a prior art transparent touch panel. As shown in the exploded perspective view of FIG. 7, this transparent touch panel is constructed by laminating a movable substrate 110 and a fixed substrate 130 via a spacer 140, which is a double-coated adhesive tape. The thickness of the double-coated adhesive tape is usually about 50-100 μm. The movable substrate 110 has an input operation surface on the front surface, which receives data input to the transparent touch panel by an operator using a pen or a fingertip.
The spacer 140 is formed into a frame-like shape, and adhered along the periphery of the movable substrate 110 and the fixed substrate 130. The spacer 140 comprises an excised section 141 that functions as an air vent, and a notch 142 to which a connector 120 (described later) is attached. When an air vent is unnecessary, the excised section 141 may not be provided.
Dot spacers 160 are provided with a predetermined interval between each other in the space between the movable substrate 110 and the fixed substrate 130 and surrounded by the spacer 140. A transparent electro-conductive layer 111 and a transparent electro-conductive layer 131 are formed on substantially the entire opposing surfaces of the movable substrate 110 and the fixed substrate 130 except for the periphery. The transparent electro-conductive layer 111 formed on the movable substrate 110 has a pair of electrodes 112, 112, with one each disposed on each of the two ends. Lead-out terminals 114, 114 are connected to the pair electrodes 112, 112 via a surrounding circuit 113 formed on the periphery of the movable substrate 110.
The transparent electro-conductive layer 131 formed on the fixed substrate 130 has a pair of electrodes 132, 132, with one each disposed on each of the two ends. The pair electrodes 132, 132 are arranged so that they are perpendicular to the pair electrodes 112,112 provided on the movable substrate 110. Lead-out terminals 134, 134 are connected to the pair electrodes 132, 132 via a surrounding circuit 133 formed on the periphery of the fixed substrate 130.
The connector 120 comprises connecting terminals 122, 122 on its top surface for being connected to the movable substrate 110, and connecting terminals 123, 123 on its bottom surface for being connected to the fixed substrate 130. Thermocompression bonding, etc., is used to attach the connector 120 to the notch 142 of the spacer 140, thus connecting the connecting terminals 122, 122 and the connecting terminals 123, 123 to the lead-out terminals 114, 114 and lead-out terminals 134, 134 respectively.
Recent years have seen a demand for reducing the number of parts used in various equipment, in order to achieve miniaturization or cost reduction. However, when a connector 120 is used as in the above-described transparent touch panel, it is difficult to reduce the number of parts. In particular, remarkable drawbacks exist in using a connector in portable electronic apparatuses, such as portable personal computers, mobile telephones, and personal digital assistants.
Japanese Unexamined Patent Publication No. 1989-221831 discloses a transparent touch panel that can be connected to an external device without using an additional connector. This transparent touch panel has a structure wherein the portion corresponding to the connector is integrally formed with a movable substrate that is constructed of a transparent film. However, because this portion projects from the periphery of the rectangular movable substrate, trimming loss that occurs in the transparent film when forming the movable substrate increases, and therefore there is room for further improvement in terms of cost reduction.